My Basic Knowledge: Creating Oracle ASM instance (Manually)

Following steps can be performed to create the ASM manually

Directory creation for ASM instance
Parameter file creation (PFILE)
Start the ASM instance
Create the ASM server parameter file (SPFILE)

Directory Creation for ASM instance:

Assuming you have defined $ORACLE_BASE parameter, following are the set of commands that can be used while creating the directories on LINUX, or you may change if you are on windows

mkdir -p $ORACLE_BASE/admin/+ASM/bdump
mkdir -p $ORACLE_BASE/admin/+ASM/cdump
mkdir -p $ORACLE_BASE/admin/+ASM/hdump
mkdir -p $ORACLE_BASE/admin/+ASM/pfile
mkdir -p $ORACLE_BASE/admin/+ASM/udump

Parameter file creation (PFILE):
The ASM instance will require a parameter file like any other Oracle instance. However, the number of parameters that you will need to set for an ASM instance is relativity small and also some parameters are unique to ASM instance. Here is an example ASM parameters

# ASM_DISKGROUPs=’DISK GROUP_1’

background_dump_dest=/u01/app/oracle/admin/+ASM/bdump
core_dump_dest=/u01/app/oracle/admin/+ASM/cdump
user_dump_dest=/u01/app/oracle/admin/+ASM/udump

instance_type=asm
compatible=11.1.0.6.0
remote_login_passwordfile=exclusive

Start the ASM instance :

The ASM instance can be started however, error will be generated (no disk group mounted) since the disk group has not been added as yet. You may refer my another article

Create ASM server parameter file (SPFILE)

After starting the instance, create SPFILE from PFILE as shown below
create spfile from pfile=’/u01/opt/oracle/admin/+ASM/pfile/init.ora’;

If you are looking to create ASM via DBCA, please refer my article below

http://www.mybasicknowledge.com/2012/06/creating-asm-instance-dbca.html

if you wanto setup test ASM instance.

http://www.mybasicknowledge.com/2012/06/configure-asm-on-test-server-without.html

Read Detailed ASM Article

http://www.mybasicknowledge.com/2012/06/oracle-automatic-storage-management-asm.html